Nelson johnson



( Modem N. JOHNSON.

SAW TOOTH.

No. 313,427. Patented Mar. 3, 1885.

' citizen of the United States, residing at Jasper,

NELSON JOHNSON, or

TENT FFIQE.

JASPER, NEW YORK.

SAW-TOOTH.

$Pl-3CIFICATION forming part of Letters Patent No; 313,427, dated March 3, 1885.

(Model) To all whom it may concern:

Be it known that I, NELSON JOHNSON, a

in the county of Steuben and State of New York, have invented certain new and useful Improvements in Saw-Teeth, of which the following is a specification.

My invention relates to that class of sawteeth which are adapted to be inserted in corresponding seats or sockets in the saw-plate and held therein by a spreading heel formed by slitting the base of the tooth.

My invention has for its object the provision of means whereby the teeth may be swaged or upset without turning them in their seats or in any other way displacing them.

In order that my invention may be fully understood, I will proceed to describe it with reference to the accompanying drawings, in which Figure I is a side elevation of a portion of a saw-plate with'my improved tooth in placetherein; and Fig. II is a section thereof on the line II II, Fig. I.

1 represents the insertible tooth, and 2 the saw-plate provided with a seat therefor, which is formed with edges which are in every respect complementary to those of the said tooth. The back of the tooth is constructed on an arc of slightly more than one hundred and eighty degrees in length, so as to be held snugly to its seat and be confined to a strictly rotary movement upon its axis, and terminates in an arc of slightly more than ninety degrees in length, as shown. It will now be apparent that any pressure upon the end of the tooth will have a tendency to rotate it on its axis; hence it is necessary that the plate should have an offset for the heel to bear against. This offset is preferably arcuate, and should be more than ninety degrees in length, for. the reason that if it is less there would be nothing to prevent the correspondingly-shaped heel from riding up it when the pressure is sufficient to deflect the parts; but when the offset is more than ninety degrees it will tend to hold the heel securely to its seat.

It will be seen on reference to Fig. I that a production, 2, of the line forming the face of that portion of the abutment which lies beyond the ninetieth degree will converge with a line, 3 y, drawn from the commencement 1 of the abutment and through the axis of the tooth. This is the equivalent of constructing the end of the tooth and its seat on a line the precise curves herein shown, although they are preferable. They may have any other regular or irregular shape so long as the heel of the tooth (or a portion thereof) and its abutment are formed on a line more or less convergent with aline drawn through the axis of the tooth and more than one hundred and eighty degrees from the commencement of the circular back thereof.

As an additional means of preventing the turning of the tooth in its seat, it is provided with an offset, 3, which abuts against the sawplate at the outer extremity of the seat. The heel of the tooth is provided with a projecting lug, 4, and a spring-slot, 5, which permits the expansion thereof for forcing the lug 4 into engagement with a corresponding notch in the saw-plate. The innermost extremity of the slot 5 terminates in a circular or other enlarged hole, 6, which increases the elasticity of the jaw and lessens the liability of its becoming fractured when compressed. The expansion of the heel may be accomplished by the springing of the metal itself; but it is preferable to accomplish it by means of a dovetail wedge, 7, which affords a firmer bearing to swage against. This wedge is made slightly tapering, as shown, and the cavity in the tooth within which it is received is flared or countersunk at the smaller end, as shown at 8, so as to permit the upsetting or riveting of the wedge 7 to retain it in place.

Having thus described my invention, the following is what I claim as new therein and desire to secure by Letters Patent:

1. The combination, with a saw-plate havin g a circular seat therein extending more than one hundred and eighty degrees in length, terminating in a circular abutment of less radius than the said circular seat, extending more IOO 2. The combination, with a saw-plate hav- 1y of the tooth andflared or countersunk on one ing a circular seat therein extending mor 2 than one hundred and eighty degrees in length, ter-' minating in a circular abutment of less radius than the said circular seat, extending more than ninety degrees in length, and having a notch at its extremity, substantially as described, of an insertible tooth formed with edges complementary to those of the seat havroing a lug projecting from the heel thereof, a

springslot, and a key inserted in said slot, in the manner and for the purpose set forth.

3. The combination, with a saw-plate having a seat therein, of an insertible tooth having a spring-heel, a tapering or wedge-shaped key for expanding said heel, and a groove for the reception of said wedge formed transverseside thereof, as and for the purpose set forth.

4. An insertible saw-tooth having a spring slot in its heel terminating at its outer extremity in a dovetail groove or mortise flared at one end, in combination with a dovetail key made tapering toward one end, as and for the purpose set forth.

5. An insertible saw-tooth having a springslot terminating at its opening in a transverse groove, in combination with a key inserted in such groove and expanding said slot, as and for the purpose set forth.

NELSON JOHNSON.

Witnesses:

L. CASE, S. BEACH. 

